What is the purpose of a Matte Box?

Yes, I've google'd, and Wikipedia'd the topic with no success. I can only find information on what a Camera Matte Box is, but not what it's for.

 

To put it quite simply, they aid in getting rid of lens flares. Flares happen when a strong light source reflects on the glass of the lens, intstead of passing through. On set you try to minimize the amount of light that hits the lens itself. By putting a mattebox on the camera, you're automatically killing a number of hits on the lens, and cutting down on the amount of work you'll have to do later.


- Rico

 

The main purpose for indy filmmakers is to make the camera look cool or "more important".

 

That's true!

Applying a matte box on a consumer camcorder you can eventually motivate your amateur crew subconsciously with your pseudo- professional camera!

Edit: Fixed smiley.

 

In traditional photography, matte boxes are also used to hold filters and (oddly enough) mattes for creating various effects and permitting double exposure effects.

The primary practicle reason they're used on video cameras is (as mentioned above) to keep stray light from outside the camera's field of view, from getting into the lens, resulting in lens flares.

Have fun.

 

What is a "double exposure effect"? Does it mean the image gets exposed twice? How does it look like?

 

Read here

I'm not sure if that article deals with double exposure but I think it does.

 

In traditional photography (that uses that old plastic stuff called "film" )....
A matte and matte box would be used when a "double exposure" composite photo effect was to be taken.

The matte is just a piece of cardboard.
The photographer would cut a hole in the cardboard, saving the piece that was cut out, resulting in two mattes that match each other.
The two resulting pieces would each be mounted onto a glass plate that fit into the matte box.
One of the two mattes would be put into the box on the lens, and a photo could be taken. Only the areas of film in the OPEN area of the matte would be exposed.
Then, the matte would be taken out and the OTHER matte would be placed into the box.
A second photo (of something different, or maybe the same person moved to a different place in the scene) would be taken WITHOUT ADVANCING THE FILM.

So the same frame got exposed twice.... double exposure, and the mattes were used to "key" the comp.

This is a very simple example.
Eventually, people started painting the masks to create scenes around the photosubject ..... resulting in Matte Paintings.

Have fun.

 

Thanks for the explanation. I remember seeing the technique in one of the old ILM books. While we're at matte paintings: How did they achieve traveling mattes with the double exposure technique? Today we use masks or whatever for creating mattes but they didn't have those 20 years back.

 

Sure they did, they just had to ...
a) paint them by hand with ink on clear plastic cels. (One of the guys I worked with last year did this for the roto work he did on ESB, ROTJ, ET and other ILM films of the day)

b) "key" them using special exposure and chemical techniques on film (bluescreen).
There's no UI sliders or "levels" filter to tweak the key or handle color matching.
Just variations in exposure time and chemical emultions.

Traveling mattes weren't used for motion film effects the same way as a "double exposure" technique was used in film photography, though.
Instead, an "optical printer" would be used to composite two seperate film shots using a traveling matte created by roto or keying techniques. Essentially, an optical printer was two (or more) film shots in projectors, "comped" with the traveling matte film, filmed by another camera.

Have fun.

 

Uncle Travelling Matt?
[image=http://www.mts.net/~arphaxad/matt.jpg]

 

Nice explenation of the matte box history It was also used at times to do other timpler optical effects like "Looking through the keyhole" they would but in a matte the shape of a keyhole to shoot through.

In modern day film/video work it is used to help with blocking exess light from hitting the lense as well as holding filters.

Now some people might argue that you dont need a matte box for filters since the average prosumer camera can have filters screwed on to the lense, but you should also take into account that not all prosumer cameras have stable lenses (ie the end of the lense doesnt spin when adjusting focus/zoom) or more often is the case are using more traditional lenses either on XL seriers cameras or when using 35mm Lense adapter systems lik the Mini35.

Now you might ask whats the big deal with spinning lenses? Gradiated Filters my son. If you screw a gradiated filter to the end of a spinning lense, the grad will spin to. Imagine that perfect orange sunset sky spinning as the character walks away and suddenly its a very bright blue sky and a yucky orange landscape So most people will use the matte box to hold 3x3 or 4x4 gradiated filters in front of the lense as well.

 

Which ones don't?


- Rico